A variety of parts feeders are well known in the prior art. Such parts feeders are often used in the manufacturing industry to present parts for pick and place type operations by a robot. Typically, such parts feeders may include various types of hoppers, vibratory-type bowls or centrifugal-type bowls containing a reservoir or bulk source of parts. These devices are used to separate and orient parts and properly present such parts for subsequent operation such as, for example, a pick and place robot. These part feeding devices are typically capable of feeding one part type or a very small family of parts.
Machine vision based flexible part feeder devices are becoming more widely used across a variety of manufacturing industries. With the use of such vision-based parts feeders, manufacturers are able to add flexibility to their manufacturing processes by designing feeders with the capability of feeding a variety of different parts. Parts feeders which can present a variety of different parts should allow the automated production of smaller volume products by making such automation more cost effective in that the same parts feeding operation can be used to supply parts for a variety of different products. Typically, in operation, parts feeders deliver both parts from a source to a transport service for inspection and subsequent picking therefrom by a multi-axis robot. A vision based inspection system is used primarily to identify which parts may be successfully grasped by the robotic picking device as well as the location of each identified "pickable" part. Flexible parts feeders also typically include a system for recirculating parts which cannot be grasped by the robot such that those parts will ultimately be presented to the robotic picking device, hopefully in a "pickable" orientation.
Parts on the transport surface typically come to rest in a stable orientation which, in many cases, is not the orientation required by the assembly operation or for placement into a part storage tray or part feeding track. The robotic picking device which picks and places these stably oriented parts must have the ability to reorient the acquired part to a more desirable orientation. This function typically requires an additional actuator mounted to the robotic arm in order to rotate the part picked. Certain types of commercially available robotic picking devices are used to accomplish the desired part picking and reorienting functions. Such picking devices may comprise two-position pneumatic and magnetic actuators, as well as various mechanical mechanisms which all add to the complexity, cost and weight of the robotic picking device. Desired additional control of the rotational function of these robotic picking devices in order to reorient the parts may be achieved by incorporating actuators such as programmable stepper motors or feedback-controlled servo motors which further increase picking device complexity, cost and weight.